//package com.dxy.yesas2020goals.study.partone.disignpattern.explainpattern.calculate;
//
///**
// * Created by Tom.
// */
//public class Test {
//
//    public static void main(String[] args) {
//        System.out.println("result: " + new GPCalculator("10 + 30").calculate());
//        System.out.println("result: " + new GPCalculator("10 + 30 - 20").calculate());
//        System.out.println("result: " + new GPCalculator("100 * 2 + 400 * 1 + 66").calculate());
//    }
//
//}
